Reduction of voltage stress in integrated high-quality rectifier-regulators by variable-frequency control

The Integrated High-Quality Rectifier-Regulators (IHQRRs) suffer from relatively high stress on the internal-energy storage capacitor and, consequently, on primary-side semiconductors. As a result, they are not practical in applications with the universal input-voltage range. In this paper, a variable-frequency control that reduces the voltage stress and makes the IHQRRs suitable for universal input-range applications is described. Evaluation results of a 90 W, experimental BIBRED power converter that uses the proposed variable-frequency control are presented.